(1) Field of the Invention
The present invention relates to a fixed length data processing apparatus, in particular, to a fixed length data processing apparatus suitable for use to execute operation, administration and maintenance (OAM) of ATM (Asynchronous Transfer Mode) communication using fixed length data of 53 bytes called an ATM cell.
(2) Description of Related Art
ATM technique is being introduced for the purpose of realization of B-ISDN (Broadband aspect of ISDN) communication network so as to comply with high speed (large capacity) communications, variable bit rate communication for image, communication systems having various connection configurations such as point-to-point, point-to-n points (n is 2 or more), n points-to-n points, and the like, required presently.
For instance, in SDH (Synchronous Digital Hierarchy) transmission network [called SONET (Synchronous Optical Network) in North America], it is tried to map (store) signals for various communication services as ATM cells (fixed length data for asynchronous communication) onto a portion of payload of an SDH transmission frame [called STM (Synchronous Transfer Module), or STS (Synchronous Transport Signal) in SONET] and transmit the signal.
An ATM cell is mapped onto the transmission frame as above, a recent demand is to identify the ATM cell mapped onto the SDH transmission frame (hereinafter simply referred as a transmission frame, occasionally) as a unit and perform operation, administration and maintenance [a data (cell) processing such as a terminating processing on an OAM cell] even in the SDH transmission network.
In a ring network 1xe2x80x2 configuring the SDH transmission network shown in FIG. 48, for example, it is necessary to interpose an ATM processing apparatus 4xe2x80x2 for performing the above cell processing between SDH transmitting apparatus 2xe2x80x2 and 3xe2x80x2. Each of the SDH transmitting apparatus 2xe2x80x2 and 3xe2x80x2 is required to have a function of mapping an ATM cell on or taking out (demapping) an ATM cell from a transmission frame. Since the ring network 1xe2x80x2 (SDH transmitting apparatus 2xe2x80x2 and 3xe2x80x2) accommodates a plurality of SDH transmitting apparatus 9xe2x80x2-1 through 9xe2x80x2-n (n is an integer not less than 2) which become transmission points in a lower hierarchy, as shown in FIG. 48, the ATM cell processing apparatus 4xe2x80x2i is required to perform the above cell processing on each transmission point.
In concrete, it is necessary to separately perform the above cell processing on each transmission frame in a lower order handled in each of the SDH transmission apparatus 9xe2x80x2-1 through 9xe2x80x2-n [distinguished as an STS channel #i (i=1 through n) in each of the SDH transmitting apparatus 2xe2x80x2 and 3xe2x80x2 (in a transmission frame in a higher order)].
For this, each of the SDH transmitting apparatus 2xe2x80x2 and 3xe2x80x2 has mapping/demapping (MAP/DEMAP) units 2xe2x80x2-1 through 2xe2x80x2-n and 3xe2x80x2-1 through 3xe2x80x2-n according to the number of STS channels #i as shown in FIG. 49, for example. Each of the mapping/demapping units 2xe2x80x2-1 through 2xe2x80x2-n and 3xe2x80x2-1 through 3xe2x80x2-n includes a demapping unit 2xe2x80x2d or 3xe2x80x2d for taking out an ATM cell from a transmission frame in the upstream (UpStream) and or in the down stream (DownStream) and outputting the ATM cell to the ATM cell processing unit 4xe2x80x2-i, and a mapping unit 2xe2x80x2m or 3xe2x80x2m for storing (mapping) an ATM cell from the ATM cell processing unit 4xe2x80x2-i in a transmission frame in the upstream (UpStream) or in the downstream (DownStream) and outputting the ATM cell to another transmitting apparatus. The ATM processing apparatus 4xe2x80x2 has ATM cell processing units (data processing units) 4xe2x80x2-1 through 4xe2x80x2-n according to the number of the STS channels #i.
Each of the SDH transmitting apparatus 2xe2x80x2 and 3xe2x80x2 can thereby perform the above ATM cell mapping/demapping process for each STS channel #i by the mapping/demapping (MAP/DEMAP) units 2xe2x80x2-1 through 2xe2x80x2-n and 3xe2x80x2-1 through 3xe2x80x2-n. The ATM cell processing unit 4xe2x80x2-i can perform the above cell processing for each STS channel #i.
Namely, the ATM processing apparatus 4xe2x80x2 performs the cell processing on ATM cells in transmission frames handled by each of the SDH transmitting apparatus 9xe2x80x2-1 through 9xe2x80x2-n separately for each STS channel #i by each exclusive ATM cell processing unit 4xe2x80x2-i serially.
For instance, an ATM cell from the SDH transmitting apparatus 9xe2x80x2-1, 9xe2x80x2-2, . . . or 9xe2x80x2-n in the lower hierarchy of the SDH transmitting apparatus 3xe2x80x2 is taken out from a transmission frame in the mapping/demapping unit 3xe2x80x2-1, 3xe2x80x2-2, . . . or 3xe2x80x2-n corresponding to the STS channel #i, and sent to a corresponding ATM cell processing unit 4xe2x80x2-i according to an internal reference cell cycle of the ATM processing apparatus 4xe2x80x2.
The ATM cell undergoes the cell processing in the ATM cell processing unit 4xe2x80x2-i corresponding to the STS channel #i is mapped on a transmission frame in the corresponding mapping unit 2xe2x80x2-1, 2xe2x80x2-2, . . . or 2xe2x80x2-n, and transmitted to the SDH transmitting apparatus 9xe2x80x2-1, 9xe2x80x2-2, . . . or 9xe2x80x2-n accommodated in the lower hierarchy of the SDH transmitting apparatus 2xe2x80x2.
Each of the ATM cell processing units 4xe2x80x2-i identifies an ATM cell, and executes fault management [termination of an AIS (Alarm Indication Signal) or an RDI (Remote Defect Indication) cell] on an ALM (Alarm) cell of an OAM cell, mainly.
For instance, when the ATM processing apparatus 4xe2x80x2 receives an OAM (ALM) cell (VP/VC-AIS) indicating occurrence of a trouble within a certain VP/VC connection, the ATM processing apparatus 4xe2x80x2 notifies of a similar AIS the downstream, or when receiving an alarm (SONET alarm or the like) in a higher order than AIS, the ATM processing apparatus 4xe2x80x2 generates a VP/VC-AIS/RDI cell and sends the cell to a desired destination.
For this, each of the ATM cell processing unit 4xe2x80x2-i has, as shown in FIG. 49, for example, a cell identifying unit 4xe2x80x2a, a cell generating unit 4xe2x80x2b, a cell inserting unit 4xe2x80x2c for downstream, a cell inserting unit 4xe2x80x2 d for upstream, and a microcomputer I/F unit 4xe2x80x2e.
The cell generating unit 4xe2x80x2b generates an ALM cell (VP-AIS, VC-AIS), and sends the cell to the downstream through the DnS cell inserting unit 4xe2x80x2c. On the other hand, an ALM cell (VP-RDI, VC-RDI) in the opposite direction is sent to the upstream through the UpS cell inserting unit 4xe2x80x2d.
The microcomputer I/F unit 4xe2x80x2e has an interface to set an operation channel, operation environments and the like from a system CPU or collect maintenance and management information (ALM information and the like).
The ATM cell or the like outputted from the ATM cell processing unit 4xe2x80x2-1, 4xe2x80x2-2, . . . , or 4xe2x80x2-i is again mapped on a transmission frame in the mapping/demapping unit 2xe2x80x2-1, 2xe2x80x2-2, . . . or 2xe2x80x2-n, and receives by another apparatus which is a destination of the ALM cell.
The cell identifying unit 4xe2x80x2a in the above ATM cell processing unit 4xe2x80x2-1 holds information for identifying a cell of an OAM (ALM) cell (VP/VC-AIS) to identify a receive cell by comparing the received cell with the information. However, if the apparatus holds the identification information for each channel [virtual channel (VP/VC) in ATM communication], the apparatus has to hold the identification information for 1024 channels in one STS channel, for example, which leads to an increase in scale of the apparatus.
If a network configuration (connection configuration) of a large capacity transmission such as one-to-n, n-to-n, a variable bit rate communication or the like is complicated, the identification information on an ATM cell is inevitably increased, leading to an increase in scale of the apparatus.
When the network configuration is complicated as above, it is necessary to execute a continuity test in the network other than OAM between stations. However, in the ATM processing apparatus 4xe2x80x2 shown in FIG. 49, only the fault management for an ATM cell is executed, but the continuity test on the ATM cell base is not executed. For this reason, it is impossible to appropriately confirm connection between the stations while continuing the network operation.
In the light of above problem, an object of the present invention is to provide a fixed length data processing apparatus which efficiently holds a large volume of information for identifying fixed length data to process the fixed length data or conduct a continuity test using fixed length data in a communication network handling fixed length data such as an ATM cell and the like.
The present invention therefore provide a fixed length data processing apparatus for processing fixed length data used for an asynchronous communication to which transmission route identification information different from transmission route to transmission route is set, the fixed length data processing apparatus comprising a registration information holding unit for holding registration information necessary to identify fixed length data that is an object of a processing commonly to the transmission routes, and a data processing unit for identifying whether received fixed length data is fixed length data that is an object of a processing or not on the basis of at least the registration information in the registration information holding unit to perform a data processing for fault management in the asynchronous communication on the basis of the fixed length data when identifying that the fixed length data is fixed length data that is an object of a processing correspondingly to the transmission route.
According to the above fixed length data processing apparatus, the registration information holding unit holds registration information necessary to identify fixed length data that is an object of a processing commonly to the transmission routes, and the data processing unit performs the data processing on the basis of the registration data, so that the apparatus can be configured simply.
The present invention further provides a fixed length data processing apparatus for processing fixed length data for asynchronous communication comprising a request generating unit being able to generate an execution request for a continuity test processing in order to confirm a continuity state in the asynchronous communication, and a continuity test processing unit for generating fixed length data for a continuity test when receiving the execution request form the request generating unit, transmitting and receiving the fixed length data to and from another fixed length data processing apparatus via the transmitting apparatus to execute the continuity test processing, and notifying a result of the continuity test processing the request generating unit.
According to the above fixed length data processing apparatus, the request generating unit generating an execution request for a continuity test processing in order to confirm a continuity state in the asynchronous communication, and the continuity test processing unit generates fixed length data for a continuity test when receiving the execution request from the request generating unit, transmits and receives the fixed length data to and from another fixed length data processing apparatus via the transmitting apparatus to execute the continuity test processing, and notifies of a result of the continuity test processing the request generating unit. It is therefore possible to readily execute a continuity test using fixed length data in an asynchronous communication network, and appropriately confirm a connection between stations in the continuity test while continuing an operation of the network.